Hydraulic systems are typically used to provide strong forces found in heavy-duty machinery. Hydraulic systems are found in heavy construction equipment, such as, cranes, bulldozers, excavators, dump trucks, forklifts, graders, as well as in large agricultural machinery, such as, tractors, combines, etc. The hydraulic/pneumatic systems currently used suffer from a lack of precision in control. Electric motors are often substituted for hydraulic/pneumatic systems in light duty machinery to accomplish precision control. Examples of precision control using electric motors include robots that are used in automobile manufacturing and in circuit board assembly industries. Such robots have sub-millimeter precision and are useful for light-duty applications. Heavy machinery applications typically mandate the use of hydraulic systems; however, exact control usually cannot be achieved.
Leakage of hydraulic/pneumatic fluid from one side of a piston to the other side results in undesirable movement in machinery, for example, in attempting to steady the position of a fire engine ladder or of a crane during installation of steel beams. A feedback control system in conjunction with an apparatus that senses a piston position could correct the slippage of hydraulic/pneumatic pistons.